In recent years, in the production of semiconductor elements and liquid crystal display elements, advances in lithography techniques have lead to rapid progress in the field of miniaturization. Typically, these miniaturization techniques involve shortening the wavelength of the exposure light source. Conventionally, ultraviolet radiation such as g-line and i-line radiation has been used, but nowadays KrF excimer lasers (248 nm) are being used in mass production, and mass production using ArF (193 nm) is also starting to be introduced.
On the other hand, one example of a resist material that satisfies the high resolution conditions required to enable reproduction of a pattern of minute dimensions is a chemically amplified resist composition, which includes a base resin that undergoes a change in alkali solubility under the action of acid, and an acid generator that generates acid on exposure. Chemically amplified resist compositions include negative compositions, which contain an acid generator, a cross-linking agent, and an alkali-soluble resin that functions as a base resin, and positive compositions, which contain an acid generator and a resin that exhibits increased alkali solubility under the action of acid.
Moreover, recently, lithography processes using EUV and electron beams, which represent the next generation of technology following lithography processes using ArF excimer lasers (193 nm), have been proposed and researched (for example, see patent references 1, 2, and 3).
EUV exhibits a high degree of linearity, and the exposure apparatus is usually constructed using a reflective optical system using a mirror such as a multilayer mirror.
[Patent Reference 1]
Japanese Unexamined Patent Application, First Publication No. 2003-177537
[Patent Reference 2]
Japanese Unexamined Patent Application, First Publication No. 2003-140361
[Patent Reference 3]
Japanese Unexamined Patent Application, First Publication No. 2003-75998